<!DOCTYPE html>
<html>

<head>
    <title>圆环进度条</title>
    <meta charset="utf-8" name="viewport" content="width=device-width;initial-scale=1.0" />
    <style type="text/css">
        html,
        body {
            width: 100%;
            height: 100%;
            margin: 0;
            padding: 0;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .circle-progress {
            position: relative;
            width: 200px;
            height: 200px;
            border: 1px solid #888;
        }

        .content {
            position: absolute;
            top: 0;
            width: 100px;
            height: 200px;
            margin: 0;
            padding: 0;
            overflow: hidden;
        }

        .left {
            left: 0;
        }

        .right {
            right: 0;
        }

        .circle {
            position: absolute;
            margin: 0;
            width: 160px;
            height: 160px;
            border-radius: 50%;
            border: 20px solid transparent;
            transform: rotate(235deg);
        }

        .left-circle {
            left: 0;
            border-top-color: green;
            border-left-color: green;
            animation: circle-left 5s linear infinite;
        }

        .right-circle {
            right: 0;
            border-bottom-color: green;
            border-right-color: green;
            animation: circle-right 5s linear infinite;
        }

        @keyframes circle-right {
            0% {
                transform: rotate(135deg);
            }
            50%,
            100% {
                transform: rotate(315deg);
            }
        }

        @keyframes circle-left {
            0%,
            50% {
                transform: rotate(135deg);
            }
            100% {
                transform: rotate(315deg);
            }
        }
    </style>
</head>

<body>
<div class="circle-progress">
<!--    <div class="content left">-->
<!--        <div class="circle left-circle"></div>-->
<!--    </div>-->
    <div class="content right">
        <div class="circle right-circle"></div>
    </div>
</div>
</body>

</html>